PROJECT SUMMARY & ABSTRACT This is an application from the Washington University in St Louis to participate as a Clinical Center of the Urianry Stone Disease Research Network (USDRN). We proposed three aims to address the specific needs enumericated in the RFA-DK-15-004. Urinary stone disease (USD) is major health issue causing pain and suffering to both adults and children. It is also one of the most prevalent and the most expensive urologic conditions to treat. Nearly 50% of patients experience at least one recurrence over 5 years? time. Although increasing fluid intake is generally recommended for stone formers, a Cochrane review found only one study for secondary prevention (to reduce recurrence). Patients? adherence to fluid protocol is generally poor. Ureteral stenting after stone surgeries caused significant pain and lower urinary tract symptoms (LUTS). Studies are urgently needed to identify risk factors that predict the severity and persistence of stent-related pain and LUTS, and to mitigate the suffering. There is also a lack of national biorepository devoted to urinary stone translational research. We have assembled a multidisciplinary team of adult and pediatric urologists, nephrologists, pain researcher, clinical trial specialist, behavioral scientist, radiologists, and emergency department researchers to address the critical research needs of urinary stone disease. We propose the following three specific aims: Aim 1: To perform a multi-center, prospective randomized, double-blinded placebo controlled trial to study the impact of increased fluid intake on stone recurrence using individualized water prescriptions AIM 2: To identify risk factors that predict the severity of stent-related pain and lower urinary symptoms with the stent in situ, and the persistence of pain and symptoms after stent removal AIM 3: Establish a biorepository for future translational research studies of urinary stone disease Collectively these projects are responsive to RFA DK-15-004 as they address defined scientific priorities. We acknowledge the responsibilities of participating in this multicenter collaborative project.